Certain embodiments of the present invention relate to a pin grid array contact, and more particularly to an pin grid array contact that provides more efficient assembly into an electrical connector.
Connectors are known for interconnecting various electrical media components, such as printed circuit boards (PCB), discrete circuit components, flex circuits and the like. Many printed circuit boards are connected to pin grid substrates by way of ZIF (zero insertion force) connectors. Typically, ZIF connectors include single or double point contacts that connect conductive pins, which extend from the pin grid substrate, to traces on the printed circuit board. Typically, the pin grid substrate, the connector, and printed circuit board are compressed together in order to ensure a conductive path between the pins, contacts and the traces on the printed circuit board.
FIG. 1 is an isometric view of a conventional connector including pin grid substrate 10, a printed circuit board 16 and ZIF electrical connector 20. The pin grid substrate 10 includes a member 12 from which pins 14 outwardly extend. The circuit board 16 includes circuitry connected to plated through holes 18. The connector 20 includes a housing 22, contact elements 24, a cover 26 and a lever 28. The housing 22 carries a number of regularly spaced cavities (not shown), positioned below the pins 14. A groove 54 is open at one end 60 to accommodate the lever 28.
Two blocks 64 with holes 66 therethrough are located on each side of the housing 22. The holes receive roll pins 68. The blocks 64, holes and roll pins 68 cooperate with structures on the cover 26 to hold the cover on the housing 22. The cover 26, preferably molded with the same material as the housing 22, contains vertical openings 70 therethrough in the same number and on the same spacing as cavities in the housing 22.
Cam block 74 extends down below the lower surface 76 of the cover 26 and is channeled along its downwardly facing surface as indicated by reference numeral 78. One corner of the cover 26 adjacent end 80 is recessed as indicated by reference numeral 82 to provide room for the lever 28.
Blocks 84 extend downwardly from opposing sides 86 and 88 of the cover 26. Both blocks 84 are outwardly displaced relative to the vertical plane of the sides. Further, the block 84 on side 86 is displaced downwardly, relative to top surface 72, to provide a space for the arm of lever 28. Each block contains an aperture 90 in each end face to receive roll pin 68. One section of the member 92 extends outwardly from that side.
The lever 28, a one piece member, includes handle 96 and cam section 98. The cam section 98 is perpendicular to the handle 96. A short connecting piece 100 joins the handle 96 and cam section 98 and displaces one relative to the other. After loading the contact elements 24 into the cavities, the lever 28 is placed into the housing 22. The connecting piece 100 and the handle 96 extend out of the groove through open end 60.
The cover 26 is placed onto the top surface 32 so that blocks 84 slide in between blocks 64 and block 74 enters into the enlarged portion 58. The cover 26 is slidably attached to the housing 22 by sliding the roll pins 68 into the holes 66 in blocks 64 and the apertures 90 in the blocks 84. The cover 26 is actuated against the top surface 32 of the housing 22 by the pivoting handle 96 of the lever 28. Thus, the lever 28 provides the actuation necessary to mate the pins 14 with the contacts 24.
The contacts 24 may contact the pins 14 at a single point, or at two points. Typically, a contact 24 that contacts a pin 14 at a single point is less reliable than a contact 24 that contacts a pin 14 at two points. A contact 24 that contacts a pin 14 at two points, moreover, is a redundant contact system. A redundant contact system is more reliable than a single contact system in that if the pin is slightly out of position, while one contact may not abut the pin 14, another contact may abut the pin 14. In other words, two points of contact are better than one point of contact.
Typically, the two point contact straddles the pin 14, thereby offering another advantage over the single point contact. That is, the two point contact ensure proper positioning of the pin 14 because the pin 14 is positioned between two contact portions of the two point contact, as opposed to touching one point of contact, as with the single point contact.
Typically, two point contacts are stamped, or blanked, in conjunction with a carrier strip, from a unitary piece of conductive material. The two point contact is typically stamped such that the contact portions are oriented in a straight line. That is, one contact portion is located at one end of the line, while the other contact portion is located at the other end of the line.
FIG. 2 is an isometric view of a conventional two point contact 24. FIG. 3 is an illustration of a conventional preformed, blanked two point contact 24 attached to a carrier strip 140. As shown in FIG. 3, while in the preformed, blanked state, the contact portions 122 are aligned with one another such that the top surfaces 118 of the contact portions 122 are co-linear with each other. That is, line segment AB and line segment CD may be connected by dashed line BC, wherein line AD is a straight line. In order to form the contact, the contact portions 122 are bent as shown in FIG. 2.
Forming two point contacts through stamping or blanking, however, produces wasted material. As shown in FIG. 3, the stamped, preformed contact typically must be sufficiently wide to allow the proper size of the contacting portions 122, while at the same time ensuring that the contacting portions 122 will align with, or mirror, each other when the contact is formed. As a result, a greater portion of conductive material is wasted during the stamping process as compared to the stamping of a single point contact.
Further, unlike single point contacts, double point contacts typically cannot be stamped the same distance apart, that is, stamped on the same pitch, as that of the cavities in the connector housing. Typical connector housing cavities, or receptacles are positioned 1.27 mm, or 0.05xe2x80x3, apart from one another. However, stamped double point contacts typically cannot be stamped that same distance from each other. The pitch, or spacing, between center lines of formed contacts on a carrier strip may be 0.10xe2x80x3. Thus, when the double point contacts are inserted into the cavities, the contacts are individually inserted into the housing cavities. Alternatively the double point contacts may be skip inserted into the contacts because the contacts may be spaced twice the distance between the cavities of the connector housing. For example, a connector housing may include a matrix of 24 cavities by 24 cavities. If the contacts are skip inserted into a row (or column) of the matrix, 12 contacts may be inserted at one time. That is, the double point contacts may be stamped on double the pitch as that of the cavities.
Thus a need has existed for a more efficient way of method of stamping, or blanking double point micro pin grid array contacts. Further, a need has existed for a more efficient method of inserting double point pin grid array contacts into cavities or receptacles of a connector housing.
In accordance with certain embodiments of the present invention, A pin grid array contact has been developed that comprises a planar main body defining, and arranged within, a primary contact plane. The main body has edges along opposed sides and along opposed ends. The contact also includes first and second spring beams integral with the main body and extending from a common one of the edges by different first and second lengths, respectively. The first length being longer than the second length. The first and second spring beams are aligned with the primary contact plane while the second spring beam may aligned in the primary contact plane. Optionally the second spring beam may be aligned with the primary contact plane, but may be bent toward the first spring beam, such that the second spring beam is no longer in the primary contact plane. The contact further comprises a paddle integral with and extending from one of the edges of the main body. The paddle is configured to adhere to a solder ball. The main body includes first and second radial positioners configured for positioning the main body into a cavity, or receptacle of a connector housing.
The first spring beam includes a first contacting portion located at a distal end of the first spring beam remote from the main body. The first and second contacting portions lie in different planes; and the first contacting portion is bent into alignment with the second contacting portion. Also, the second spring beam includes a second contacting portion located at a distal end of the second spring beam remote from the main body. The first and second spring beams are shifted laterally from one another with respect to a center line of the main body. The lateral shift is in a direction parallel to the primary contact plane.
While in the flat, stamped state, the second spring beam is offset from the first spring beam by a predetermined angle. The stamped double contacts are coplanar with the carrier strip. Then, the first and second spring beams are bent such that the first and second spring beams lie in different first and second planes, while the first contacting portion remains laterally aligned with the second contacting portion.
Certain embodiments of the present invention provide a method of forming a pin grid array contact. The method comprises stamping a contact having a main body formed with first and second spring beams from a planar single sheet of conductive material, in which the first and second spring beams have different first and second lengths that extend along first and second longitudinal axes, respectively. The first and second spring beams are aligned at an acute angle with one another and initially oriented in a primary contact plane defined by the main body. The method also comprises bending the second spring beam with respect to the main body until the second spring beam is located in a second beam plane that is separate from the primary contact plane. Additionally, the method comprises shifting the first and second spring beams laterally from one another with respect to a center line of the main body. The shifting step occurring in a direction parallel to the primary contact plane. Also, the method comprises aligning a first contacting portion of the first spring beam into alignment with a second contacting portion of the second spring beam.
Certain embodiments of the present invention also provide the following steps: providing a carrier strip integral with a plurality of the contacts in the primary contact plan; positioning adjacent contacts so that a distance between center lines of the adjacent contacts corresponds to a distance between two cavities located on a connector housing; and stamping a paddle on the main body and bending the paddle to be perpendicular to the main body of each contact.